comsol convergence plot

Iterative solver, convergence plot outrunning iteration number shown in Progress tab. Contrary to the related information that COMSOL Multiphysics already provides, such as convergence numbers, which are scaled global numbers, the residual operator provides an unscaled residual value for each variable in a model. It also shows a spatial distribution of the residual for that quantity. Plot visualizing the electric potential computed by the electrostatics physics. The convergence plot for the Turbulent Flow Over a Backward Facing Step tutorial model. I will be using comsol software for research work. Plot depicting the net space charge, i.e. June 15, 2011. in COMSOL; this is the contents of Section 2. Convergence study using COMSOL Convergence study is done by changing the mesh configuration from extra coarse to extra fine. If you would like a live view of which users are consuming which licenses, with a dashboard to analyse past usage, including those potentially hoarding/abusing licenses - contact me now for a demo or free trial of LAMUM ( www.teameda.com ) In fact, that is exactly what is occurring here; the stresses at the sharp corner are non-convergent with respect to mesh refinement because we have a singularity in the model. A special case is the Convergence Plot window, an automatically generated Plot window that displays a graphical indication of the convergence of the solution process while a model is running. After the analysis is finished, display the convergence information by clicking the Convergence Plot tab on the Output Bar. Keywords: Finite Elements, convergence order, adaptive meshes, Poisson equation, potential equation 1. Patrick Ma . COMSOL; this is the contents of Section 3.3. A special case is the Convergence Plot window, an automatically generated Plot window that displays a graphical indication of the convergence of the solution process while a model is running. Plot of the residual for different values of the parameter Q. the contribution of the anions and the cations. RESULTS † Improved plot defaults that provide plots adapted to the physics in the model with descriptive names of the created plot groups. The second purpose is to explain in detail how to conduct these convergence studies in both using the graphical user interface (GUI) of COMSOL 4.0a as well as using COMSOL’s LiveLink for MATLAB. When you have convergence issues, try to get COMSOL to plot a useful value during its solving, this helps to see what is going wrong and might give a clue how to handle it you seem to get a convergence issue when the flow has fully stopped in the inlet2 if you keep a very small flow it seems to work better i.e Fl1/1000 or even 1000 times less ;)-- By default, the convergence criterion is 0.001. This is a great way of ensuring license optimisation for these expensive COMSOL licenses. Typically we would run the analysis out enough iterations such that the Automatic Convergence Assessment kicks in. Send Private Message Flag post as spam. Plot of the derivative of the residual for different values of Q. by Phil Kinnane. A COMSOL Multiphysics® simulation typically includes one or more field quantities in its output. High fluctuations are observed in pressure and velocity values. Creating a Mesh Plot. Automatic Convergence Assessment assesses convergence, and stops the analysis when the solution is no longer changing. Note that while COMSOL employees may participate in the discussion forum, COMSOL ® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team. Information Windows These are the windows for non-graphical information. Note: This discussion is about an older version of the COMSOL Multiphysics ... To start a new discussion with a link back to this one, click here. Posted 24.04.2016, 22:26 GMT-7 Studies & Solvers Version 5.2 0 Replies . If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help. User Guides. The Segregated solver settings with the plot of the residual, specified under Results While Solving. This example is a nice illustration of what happens when you solve transport problems with some sort of stationary approach — in this case, pseudo time stepping. Velocity plot showing the motion of … The convergence plot for the Turbulent Flow Over a Backward Facing Step tutorial model. Notice the fast convergence toward the end. By plotting and evaluating the algebraic residual, you can troubleshoot models that do not converge or converge slowly, so that you can find your simulation results as quickly and efficiently as possible. Convergence plots. Let’s also plot out the corresponding derivative of the residual (the Jacobian) for the same range of T and values of Q below. The positive net charge screens the negatively charged wall. Using 2 variables from 2 different solutions to make a single plot. comsol-license-agreement) и могут использоваться и копироваться исключительно в соответствии с его условиями. For improved efficiency when saving solutions on a cluster, you can now right-click a Solution node and choose Store Solution Using Distributed Storage. The COMSOL Multiphysics® software offers several different formulations for solving turbulent flow problems: the L-VEL, algebraic yPlus, Spalart-Allmaras, k-ε, k-ω, low Reynolds number k-ε, SST, and v2-f turbulence models. Troubleshoot convergence issues by plotting and evaluating your model's algebraic residual via the residual operator in COMSOL Multiphysics. Patrick Ma . where x i is the locations of the integration points and w i is the corresponding weight factors. As mesh size decreases towards zero (leading to a model of infinite size), you move toward the exact solution for the equations you are solving. Sai Ram Katikala @Sai-Ram-Katikala. The COMSOL Multiphysics ® software brings a user interface and experience that is always the same, regardless of engineering application and physics phenomena.. Add-on modules provide specialized functionality for electromagnetics, structural mechanics, acoustics, fluid flow, heat transfer, and chemical engineering. Lines 14-16 report the solution time and memory requirements. Support. A special case is the Convergence Plot window, an automatically generated Plot window that displays a graphical indication of the convergence of the solution process while a model is running. The convergence plot of the segregated solver, and the probe plot, are shown below. I am new to comsol multiphysics software. CAD Tool Quick Start Guides. Wu Jakes . The integration points are often called Gauss points, even though this nomenclature, strictly speaking, is correct only for integration points defined by the Gaussian quadrature method. Convergence plots use graphics to show how an error estimate or time step evolves during the solution process for nonlinear, time dependent, and parametric solvers. Hi Willem, the convergence plot when you are using the FFEPlus solver is actually of no use to typical users, it plots the convergence of some parameters that are internal to the solver. About the COMSOL Product Suite. Send Private Message Flag post as spam. To understand where low-quality elements are positioned and which mesh size parameters to change, it can be a good idea to perform a plot of the mesh. Learn about all of the updates relating to studies and solvers below. Distributed Solution Data Storage on Clusters These equations may be a set of independent ordinary differential equations (ODEs) or a set of coupled equations which arise as a consequence of the spatial discretization of a boundary value problem (BVP) via the finite element method (FEM). Send Private Message Flag post as spam. The second purpose is to explain in detail how to con-duct these convergence studies in COMSOL 4.0. When I look at the Convergence Plot 2, which is "Reciprocal of step size" vs "Time step", I can see the reciprocal of step size is between 10^5 and 10^6. Depending on the number of field quantities, the geometry’s complexity, and the mesh density required for valid results, simulations can include millions of degrees of freedom (DOFs). 2 Elliptic Test … It has to do with the deviations that occur from successive calculations of a value. Tutorials and Training Materials. 03 October 2020 3 4K Report. Introduction The convergence of a numerical solution towards the analytical solution of a set-up of one or For example, you can plot residual(spf.U) to get a plot of the latest residual of the velocity U in a fluid-flow simulation. Convergence plot Posted 21 giu 2019, 03:44 GMT-4 Heat Transfer & Phase Change, Computational Fluid Dynamics (CFD) 0 Replies Sreekar Reddy However, since we are limited by finite comp… Posted 24-Aug-2015, 1:09 am GMT-7 Studies & Solvers Version 4.3 1 Reply . The less change that occurs with each iteration, the closer it gets to an exact solution. The second purpose is to explain in detail how to conduct these convergence studies in both using the graphical user interface (GUI) of COMSOL 4.0a as well as using COMSOL’s LiveLink for MATLAB. For example, you can plot residual(spf.U) to get a plot of the latest residual of the velocity U in a fluid-flow simulation. Application Notes. Think of each iteration as an educated guess. Mahvash Afzal . in COMSOL; this is the contents of Section 2. Send Private Message Flag post as spam. I have tried to define point sinks in the geometry. An update of this note for COMSOL 4.0a and ex-tension to using LiveLink for MATLAB is the topic of [6]. COMSOL Multiphysics ® version 5.5 includes cluster computing improvements, new mesh adaptation functionality, faster solvers, and more. The residual can provide insight into convergence issues by showing the locations where the algebraic residual is large. I am Sairam, doing a PhD in Civil Engineering at IIT Bombay. The COMSOL Multiphysics ® software brings a user interface and experience that is always the same, regardless of engineering application and physics phenomena.. Add-on modules provide specialized functionality for electromagnetics, structural mechanics, acoustics, fluid flow, heat transfer, and chemical engineering. After the analysis is finished, display the convergence information by clicking the Convergence Plot tab on the Output Bar. About the COMSOL Product Suite. This is a clear indicator that boundary conditions or the mesh quality might be responsible for numerical issues at the outlets. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help. Whenever you use the finite element method, it is important to remember that the accuracy of your solution is linked to the mesh size. × Warning Your internet explorer is in compatibility mode and may not be displaying the website correctly. Kind regards, Prasad Bhonsule. Posted 9 sept. 2018 à 14:12 UTC−7 RF & Microwave Engineering, Results & Visualization, Studies & Solvers 0 Replies to use LiveLink for MATLAB for the convergence study to be carried out in a convenient automated fashion, and more. The direction of solar radiation is set up to replicate the conditions at the hotel’s pool in the month of September at the time of 11:30 a.m. 2018 à 03:10 UTC−7 Mesh, Studies & Solvers, Structural Mechanics & Thermal Stresses Version 5.0 0 Replies They include: † Messages: Various information about events of the current COMSOL COMSOL Multiphysics v4.2 Release Highlights. I need results for this simulation by the beginning of next week. Let’s check the Outlets convergence plot of a successful simulation. of boundary elements Extra coarse 379 180 Coarser 534 195 Coarse 667 206 It has been like this for several hours, and the progress value is at 2% without increasing. Understanding the Convergence Plot, and 'Undefined Value in Equation Residual Vector' Posted 16 oct. 2014 à 04:22 UTC−7 2 Replies . Obtained number of domain and boundary elements for each configuration is as follows: Mesh configuration No. Please find attached a convergence plot of a nonlinear model computation (created automatically in COMSOL). One image uses log-axis for the relative error, while the other uses a linear axis scale. Here the convergence criterion is set to 1e-6 (=0.0001% relative error / tolerance) and it took 16 iterations to reach convergence. When solving such a problem, you will get a Convergence Plot, which shows the error estimate decreasing between Newton-Raphson iterations. studied cases the convergence rate of COMSOL numerics is identical to the theoretically derived convergence rates. Outlets convergence plot shows some serious issues. Ideally, the error should go down monotonically if it does converge, then start investigating ramping the loads, the nonlinearities, or the multiphysics couplings. COMSOL BV Röntgenlaan 37 ... † Convergence plots for monitoring convergence of nonlinear, iterative, and time-dependent solvers. The primary criteria for determining convergence is that the change of each degree of freedom is minimized over a large range of iterations.

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